One important difference is in the rates of survival. The study found that while survival for men with breast cancer has improved, it hasn't kept pace with the strides made in treating breast cancer in women.

"Although we saw a significant improvement in overall survival for male breast cancer patients over time, the prognosis for men with breast cancer has not been improving as much as for women with the disease," Dr. Fatima Cardoso, director of the breast unit at the Champalimaud Cancer Center in Lisbon, Portugal, said in a news release from the American Association for Cancer Research.

"This is largely because male breast cancer is a rare disease -- it accounts for just 1 percent of breast cancers -- and we know very little about its biology and how best to treat patients," Cardoso said.

In the new study, Cardoso and her team followed more than 1,800 men with breast cancer. The men were diagnosed between 1990 and 2010 and they were treated at 23 medical centers in nine countries. The average age of men at diagnosis was almost 69 years old, the study reported.

The researchers found that only 77 percent of men got endocrine therapy such as tamoxifen for their cancer when it was indicated. They also found that even though 56 percent of the cancers were diagnosed when the tumors were very small, only 4 percent of the men had breast conserving surgery. Most had a mastectomy, Cardoso found.

Most of the men, 92 percent, had cancer known as estrogen receptor positive, the kind that requires estrogen to grow. In women, 70 percent of breast cancers are ER-positive.

Far fewer of the men's cancers were of the types known as HER2 and triple negative, which occur in women, the researchers found.

After a follow-up of nearly six years on more than 1,000 men, 63 percent were still alive, according to the study.

Cardoso is due to present the findings Dec. 9 at the 2014 San Antonio Breast Cancer Symposium. The symposium is a partnership of the University of Texas Health Science Center, the American Association for Cancer Research and Baylor College of Medicine.

Studies presented at medical meetings are generally viewed as preliminary until published in a peer-reviewed medical journal.

The study conclusions ring true, said Dr. Courtney Vito, assistant clinical professor of breast and surgical oncology at City of Hope Cancer Center in Duarte, Calif. Vito has conducted similar research and says the new findings echo many of her findings.

"The problem is, men tend to present later [for treatment]," she said. "And men don't always get the treatment they need."

Some men notice a symptom, such as a lump, and brush it off, never thinking about the possibility of breast cancer, Vito said. "Men should take a lump in the breast as seriously as a woman should," she said. "Any man who has breast cancer deserves genetic testing," she added, to see if the cancer is driven by genetic risks.

Men who notice a change in breast skin, such as redness, or a change in appearance of the nipple, or a discharge, should get it checked out, she said.

Dr. Christopher Pezzi, director of surgical oncology at Abington Memorial Hospital in Abington, Pa., recently reported on 13,000 cases of male breast cancer. The new findings are largely in keeping with his research.

"Overall, we also did find significant differences between breast cancer occurring in men and women. But it is also worth noting that we also found that there was a great deal of similarity and overlap in the disease presentation, and many areas where the tumors presented and behaved in very similar ways," Pezzi said.